Electro-oxidation of ethanol of PtPdSn/C-Sbsub(2)Osub(5)-SnOsub(2) electrocatalysts prepared by borohydride reduction

Abstract

Pt/C-Sb2O5.SnO2, PtPd/C-Sb2O5.SnO2 and PtPdSn/C-Sb2O5.SnO2 electrocatalysts were prepared in a single step using H2PtCl6.6H2O, Pd(NO3)2.2H2O and SnCl2.2H2O as metal sources, sodium borohydride as reducing agent and a physical mixture of 85% Vulcan Carbon XC72 and 15% Sb2O5.SnO2 (antimony tin oxide – ATO) as support. X-ray diffractograms showed that Pt-Pd-Sn(fcc) alloy, carbon and Sb2O5.SnO2 phases are present in the PtPdSn/C-Sb2O5.SnO2 electrocatalysts. Transmission electron microscopy for all electrocatalysts showed that the metal nanoparticles were homogeneously distributed over the supports with average particle sizes in the range of 3-5 nm. The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at 25oC and in a single Direct Ethanol Fuel Cell (DEFC) at 100oC. PtPdSn/C-Sb2O5.SnO2 electrocatalysts exhibited superior performance for ethanol electro-oxidation than PtPd/C-Sb2O5.SnO2 and Pt/C-Sb2O5.SnO2 electrocatalysts, respectively. In situ FTIR studies showed that acetic acid and CO2 are preferentially formed using PtPdSn/C-Sb2O5.SnO2 electrocatalysts.